1. Field of the Invention
The present invention relates to a dustproof structure and a dust entry preventing method in an electronic device and the electronic device employing the structure and method and more particularly to the dustproof structure and the dust entry preventing method employed in, for example, a portable-type electronic device such as a foldable portable cellular phone using a screen component to protect a display panel as a diaphragm which is attached to a cabinet with a gasket member interposed between the diaphragm and the cabinet, and to the electronic device having the structure and using the dust entry preventing method.
The present application claims priority of Japanese Patent Application No. 2004-378312 filed on Dec. 27, 2004, which is hereby incorporated by reference.
2. Description of the Related Art
In recent years, due to high versatility of being usable even during movement of a user or while on a road, a portable electronic device such as a portable cellular phone is now in widespread use. Popularity has been gained by many users to a foldable and freely opened-closed type portable cellular phone, in particular, since the portable cellular phone can be housed in a compact state. The foldable portable cellular phone has become commercially practical which is so configured that, by using a two-shaft hinge, one cabinet is allowed to freely rotate relative to another cabinet in a portion surrounding one rotational shaft mounted in a direction perpendicular to another rotational shaft used to open or close the cabinet.
In a portable cellular phone 101, as shown in FIGS. 15 and 16, an upper unit 102 and a lower unit 103 are connected to each other by a two-shaft hinge 104 and, on an upper cabinet 105 of the upper unit 102 are mounted a speaker section 106 to output a received voice and a display section 107 made up of a liquid crystal display device and, on a lower cabinet 108 of the lower unit 103 are mounted an operating section 109 made up of various operational keys, a microphone section 110 to receive a transmitting voice, and a voice outputting section 111 having a speaker.
Moreover, the display section 107, as shown in FIG. 17, has a liquid crystal display panel 112 and a backlight to supply illuminating light to the liquid crystal display panel 112, all of which are held by a holding frame 113 and are mounted in the upper cabinet 105. Also, a screen component 114 to protect the liquid crystal display panel 112 is bonded to a front case 115 by using a double-faced adhesive sheet 116.
The portable cellular phone 101 having, in addition to its original telephone conversation function, a data communication function of receiving and transmitting electronic mail and/or of being connected to the Internet to browse home pages is widely used. In the above portable cellular phone 101, for example, when a user runs a program downloaded from a site to play a game, in order to hear a voice while viewing a screen of the display section 107, the portable cellular phone 101 is used with cabinets 105, 108 being opened.
However, the conventional portable cellular phone 101 has a problem. That is, as shown in FIG. 16, when a user views a display screen of the display section 107 in a state in which the portable cellular phone 101 is folded in a compact manner with the display screen faced toward a front, the user cannot hear a voice satisfactorily since the speaker of the voice outputting section 111 is hidden. Moreover, the user, when carrying out a telephone conversation, puts the speaker section 106 to his/her ear with the cabinet being opened, however, since a voice hole of the speaker section 106 is comparatively small, it is difficult for the user to put the voice hole on the ear exactly and the portable cellular phone 101 is displaced from a position of the voice hole, which causes an insufficient amount of a voice and an unclear voice. To solve this problem, in recent years, technology is proposed to be applied to a portable cellular phone (for voice outputting from a display screen, see Non-patent reference 1: “Nikkei Business”, the Nov. 1, 2004, Nikkei Business Publication Inc., p. 90) in which, for example, a screen component used to protect a display panel of a personal computer is to be used as a diaphragm making up a flat panel speaker of the portable cellular phone.
As is shown in FIG. 18, a flat panel speaker 201 employed in the conventional portable cellular phone 101 is mounted in a cabinet having a display section and is made of a transparent material of, for example, an acrylic resin and includes a diaphragm 202 also serving as a screen component to protect the liquid crystal display panel and an actuator module 203 having a piezo-electric element which vibrates the diaphragm 202 for emission of sound waves.
The diaphragm 202, as shown in FIG. 19, in its specified portion, is attached to the actuator module 203 so that vibration is transferred from the actuator module 203 in a manner in which the diaphragm 202 strikes the actuator module 203 to come into physical contact and also is attached to the front case 206 making up another cabinet and having an aperture 206a in its central portion to expose a display screen of the liquid crystal display panel with a frame-shaped gasket member 204 used to prevent the entry of a foreign matter such as dust or a like interposed between the diaphragm 202 and the front case 206. The gasket member 204 is placed so that its inner wall face 204 faces the aperture 206a of the front case 206 and is bonded to the diaphragm 202 by using the frame-like double-faced adhesive sheet and to an edge of the aperture 206a of the front case 206 also by using the frame-like double-faced adhesive sheet.
The problem to be solved is that the gasket member 204 is deformed due to secular changes which causes a function of preventing dust entry to be degraded and the resulting deformation interferes with, for example, a liquid crystal display panel 112 placed on an inner side (on a central portion side of the aperture) causing damage. That is, as shown in FIG. 20, the gasket member 204 deteriorates and is deformed to a degree to which the gasket member 204 is made flat (in a manner in which its thickness decreases and its width increases) making it impossible to perform the satisfactory dustproof function and, in addition, a portion extended inside, in particular, comes into contact with the liquid crystal panel 205 causing damage.